Tilting mechanism for induction furnace



Oct. 31, 1967 E. BUHRER ETAL 3,

TILTING MECHANISM FOR INDUCTION FURNACE Filed Aug. 31. 1964 5 Sheets-Sheet 1 INVENTORS ERW/N BUHRER wea on BACHTOLD /(4/?L- HEM/Z HELLMUND Oct. 31, 1967- E. BUHRER ETAL 3,350,083

TILTING MECHANISM FOR INDUCTION FURNACE Filed Aug. 31, 1964 3 Sheets-Sheet 2 INVENTORS sew/1v BU/{R'ER file-0002 BA'CHTOLD KARL -HEINZ HELL/JUNO O 1, 1967 E. BUHRER ETAL TILTING MECHANISM FOR INDUCTION FURNACE 3 Sheets-Sheet 5 Filed Aug. 31. 1964 ATTORNEYS United. States Patent D 3,350,083 TILTING MECHANISM FOR INDUCTION FURNACE Erwin Biihrer, Breitenaustrasse 164, Sch'atfhausen, Switzerland, and Theodor Biichtold, Schatfhausen, Switzerland, and Karl-Heinz Hellmund, Dortmund, Germany, assignors to said Erwin Biihrer, Schaffhausen,Switzerland Filed Aug. 31, 1964, Ser. No. 393,122 Claims priority, application Switzerland, Sept. 2, 1963, 10,836/63; June 3, 1964, 7,225/64 9 Claims. (Cl. 266- 38) ABSTRACT OF THE DISCLOSURE The construction of an induction furnace is described herein which is of a type which includes a pouring spout on one side and a slag trough or opening on another side which may be opened or closed.

A particular feature of the invention is that the furnace is pivotally supported about a substantially centrally lo cated pivot so that it may be tilted in one direction for pouring purposes and tilted in an opposite direction for deslagging or slagging and wherein the furnace is provided with an opening adjacent the pivot location which permits the continuous inflow of a molten met-a1. The arrangement is such that the molten metal may be continuously poured through the opening of the furnace even though it may be tilted for pouring or-for slagging purposes. This is possible because the pouring inlet is arranged adjacent the pivot for the furnace so that the relatively small sized opening of the furnace will be always aligned below the pouring spout.

A further feature of the invention is the mounting for the furnace which includes the pivotal support defining an axis which extends through the opening at the top or top cover of the furnace and which includes a fluid operated shiftable member which engages the furnace from one side for the purpose of tilting it about its pivotal location either upwardly for pouring purposes as represented in FIG. 3 of the drawings or downwardly for slagging or deslagging purposes as indicated in FIG. 4 of the drawings. In addition, in the preferred arrangement, the furnace may be tilted beyond the pouring direction in FIG. 3 to the pouring orientation of FIG. 5 to completely empty the furnace if so desired.

Summary of the invention The present invention broadly has reference to furnace constructions, and, in particular, to new and improved induction furnaces incorporating a cover which is pref erably rigidly mounted to and is to be considered as part of the furnace body, such furnace including a pouring spout, and wherein the furnace is only tiltable about a single horizontal axis and means are provided in order to continually feed molten iron to the furnace.

Because of the recent technical developments in the operation of foundries, the necessary smelting capacity of the smelting plant is constantly increasing. At the same time the requirements regarding the quality of the casting, and thus temperature constancy, and the analytical accuracyof the iron to be cast also increases. The development of highly mechanized or automatic molding and casting plants where the liquid iron consumption follows its own particular laws, requires, in addition, the provision of a variable equalizing amount of castable liquid iron between the smelting plants and the casting plants, since there is no buffer in the form of ready to cast molds in these casting plants. I

In order to :be able to maintain the narrow tolerances in the analytical differences and the liquid iron temperatures, and in "order to be able to make analytical cor- 3,350,083 Patented Oct. 31, 1967 rections, induction furnaces have been built, for example, with means for feeding liquid iron from a cupola furnace by means of transport vessels. A disadvantage of this type of operation, however, is that the plants are expensive to install and their operating costs are also relatively high. The high cost is partly due to the fact that the repeated transfer of the liquid iron leads to a temperature loss and such transport requires additional operating personnel. An additionaldisadvantage is the slag formation during the repeated transfer and the resulting increased gas absorption. The quantitative equalization in liquid iron between the smelting and the casting plant would only be possible by the additional installation of induction furnaces which is not feasible from an economic standpoint. Another disadvantage of the known arrangements is that they require a great deal of space.

In order to achieve the quantitative equalization of the liquid iron, liquid collectors have been arranged ahead of the cupola furnaces. These collectors permit the quantitative equalization between the smelting plant and the casting plant, but the analytical equalization and the temperature equalization have not been achieved in practical usage.

Many attempts have been made to find solutions to the above problem. For example, cupola furnaces which continually discharge liquid iron, were connected by means of a movable trough directly with the induction furnaces. Since the axis of tilt of the induction furnace is next to the pouring spout, the trough, whose outlet end is arranged above the center of the arched roof of the furnace, must perform not only lateral movements but also considerable vertical movements. At the same time the trough prevents the lifting, swinging or tilting of the induction furnace cover in operation. This type of induction furnace thus becomes exclusively heat-preserving and quantity-equalizing device for liquid iron. Thus, with such a furnace it is not possible to vary the carbon content of the liquid iron, for example, by using sheet packs or pig iron. In addition, lumpy ferrous alloys cannot be charged into the induction furnace, nor slag withdrawn over the liquid iron bath. This type of induction furnace is, therefore, no longer suitable for its main purpose, namely correcting the analysis of the liquid iron.

A further embodiment of induction furnace provides a tilt axis beneath the pouring spout for tapping the liquid iron and a second tilt axis at the opposite side of the induction furnace for slag removal. With such type arrangement it is not possible to continuously receive liquid iron from a cupola furnace.

Generally speaking, the present invention renders possible overcoming the above-mentioned disadvantages by means of an induction furnace manifested by thefeatures that, the horizontal axis of tilt is arranged above the highest level of the liquid iron and passes through the surface of the horizontal projection of the interior cross-section of the furnace. Furthermore, a charging opening is arranged at a side of the furnace opposite the pouring spout and simultaneously serving as slag removal opening. A

particularly favorable physical structure provides that the axis of tilt passes through the cylindrical axis of the in- ;duction furnace and is arranged between the highest liquid iron level and the upper edge of the furnace cover or roof.

a continuous amount of liquid iron through the opening in the cover or roof. A further embodiment of the present invention provides an opening for the pouring of liquid iron into the furnace which is substantially co-axial with the axis of tilt.

In a preferred arrangement, the furnace advantageously includes an arm portion on a side adjacent the pouring spout for pivotally supporting a ladel in a manner that the ladel is automatically maintained in an upright position during the tilting of the furnace to which it is attached or supported.

Accordingly, it is an object of this invention to provide an improved induction furnace.

A further object of the invention is to provide an induction furnace having means for pivotally supporting the furnace for tilting movement about a horizontal axis adjacent the top thereof and with the top cover having an opening which is substantially centered during the tilting movement of the furnace beneath a trough for supplying melted iron thereto.

A further object of the invention is to provide an induction furnace which is pivotally supported about a horizontal axis and which includes a pouring spout on one side arranged directly below an arm which pivotally supports a ladle in an upright position below the spout during all pivotal movement of the furnace, and which further includes a slagging spout on the side opposite from the pouring spout, the furnace being tiltable in one direction for casting, and in another direction for slagging.

A further object of the invention is to provide an induction furnace which is simple in design, rugged in construction and economical to manufacture.

Another very important object of the present invention resides in the provision of an improved induction furnace mounted to be tiltable about a horizontal axis located above the highest liquid level, this axis of tilt passing through the surface of the horizontal projection of the cross-section of the furnace interior, and in order to maintain a substantially stationary position of the liquid receiving opening during tilting of the furnace such opening is arranged in a position through which passes the aforesaid axis of tilt.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated and described a preferred embodiment of the invention.

In the drawings:

FIG. 1 is a transverse vertical section through a first embodiment of induction furnace constructed in accordance with the invention and taken along the line I-I of FIG. 2;

FIG. 2 is a top plan view of the furnace indicated in FIG. 1 in operative association with a cupola furnace;

FIG. 3 is a view similar to FIG. 1 but indicating the furnace in a casting position;

FIG. 4 is a view similar to FIG. 1 with the furnace in the slagging or charging position; and

FIG. 5 is a view similar to FIG. 1 but indicating the furnace in the maximum tilting position during casting.

Referring now to the drawings and, in particular, to the embodiment of induction furnace depicted in FIG- URES 1 to 5, it will be understood that such induction furnace, generally designated by reference numeral 4, is shown in FIG. 2 in operational use with a cupola furnace 1. A trough 2 which is secured to the cupola furnace 1 extends outwardly therefrom to a position overlying the induction furnace 4 at a location of an opening 5 in the induction furnace cover 6, considered to form part of the furnace body, for the purpose of continuously supplying liquid iron 3 thereto. The liquid iron flows through the opening 5 in the furnace cover 6 into the inner compartment or interior 7 of the induction furnace 4 which is closed at all sides by the furnace body which includes cover 6.

In accordance with the invention, the induction furnace 4 is pivotally mounted in side bearings 8, 8 supported on stands 9, 9, respectively. As indicated only in FIG. 2, two hydraulic tilting cylinders 10, 10 are arranged on each side and are pivotally mounted on a fixed plate 11 at their one ends and connected for articulation with a rod member 12 at the furnace 4. When the cylinders 10 are operated, they cause the furnace 4 to tilt from the normal position indicated in FIGS. 1 and 2 into the casting position indicated in FIG. 3, the slagging or charging position indicated in FIG. 4, or the maximum casting position indicated in FIG. 5.

A feature of the invention is the provision of a support 13 which receives a ladle 14. The support 13 is pivotally mounted on the furnace 4 by means of journals 15, 15a. A parallel guide is formed by an arm 16 which is rigidly connected with the stand 9 and which is pivotally connected at its free end with a bar 17 and a crank or lever 18, the opposite end of which is connected to the journal 15. A further respective arm 16a and 16b connected with the furnace 4 pivotably supports the journals 15 and 15a, respectively. During the tilting movement of the furnace 4, the arm 16 and bar 17 cause rotation of the crank 18 to cause a corresponding tilting of the support 13 to hold the ladle 14 and the support in substantially horizontal position at all tilting angles of the furnace 4. In order to provide this effect, the bar 17 corresponds in length to the distance between the axis of the bearing 8 and that of the journal 15, and the length of the lever 18 equals the distance of the joint on the arm 16 from the axis of tilt. A slot 19 is provided in the bar 17 for releasing the support 13 in backward tilting for slagging or charging, in which case it assumes the position indicated in FIG. 4 with its lower end in abutting relationship with the furnace 4.

When the liquid iron is cast by pouring from the furnace 4 into the ladle 14, the casting is done through a casting spout 50 with an opening 52 from the end of which a molten jet, indicated 20 in FIG. 3, has the shortest possible length.

In FIG. 5 which indicates the position of the induction furnace 4 in complete emptying which usually occurs at the end of the operations, the trough 2 which connects the cupola furnace 1 with the induction furnace 4 is removed. In such a position the great advantage of the parallelogram-type arrangement which permits the support 13 to be maintained in a horizontal position is particularly clear.

A charging or slagging opening 21 which is provided on one side of the furnace 4 is closed by means of a slidable door 22 which moves upwardly and downwardly in the spout portion. When the furnace 4 is tilted into a slagging position, as indicated in FIG. 4, the door 22 is opened and the slag is withdrawn so that it pours directly into the slag pot 23 bearing via pins 24 against the supports 25 fixedly connected with the furnace 4. As can be seen in FIG. 4, whereas the furnace coil 26 at end 27 is above the liquid iron bath, the portion of this furnace coil at the end 28 does not extend to the maximum filling height 29 of the iron level. This has the advantage that the power consumption with a given voltage varies less with a varying iron charge of the induction furnace of the invention. The furnace coil 26 is connected to suitable means for supplying current to the furnace 4. The casting pit, the working platform and means for charging sheet stacks, pig iron or alloys, etc. are not indicated in the drawings.

The inventive furnace is tiltable about a single horizontal axis of tilt located above the highest liquid iron level and passes through a surface of the horizontal projection of the inner furnace cross-section, and in order to maintain a substantially stationary position of the pouring or receiving opening during tilting of the furnace such opening is arranged at a location through which passes the axis of tilt; more specifically, the axis of tilt preferably passes substantially through the center of the opening so that .suchcenter remains substantially stationaryin space.

The invention permits in a most economical manner the connection of an induction furnace directly with the cupola ,furnace for continuously supplying liquid iron. When an induction furnace constructed in accordance with the invention is in operation, liquid iron can be fed to :it continuously and removed intermittently. The furnace is mounted so that it may be tilted in either direction with apouring spout on the. side for tapping and with an opening provided on the opposite side of the pouring spout for receiving a charge of sheet stacks, pig iron, ferrous alloys, etc. or the withdrawal of slag in a simple manner. The invention permits the intermittent casting of liquid iron withthe shortest possible liquid iron jet, consequently with a minimum-formation of slag (in tapping). The invention further permits quantitative equalization of the liquid .iron between the cupola furnace and the casting plant up toandat least half the entire induction furnace contents, since the induction furnace can also be operated when partly filled. Due to the charging and slagging opening provided at the furnace it is not necessary to provide a shiftable or pivotable attachment of the furnace cover; such must bedetachably connected to the induction furnace in order to undertake repairs.

The induction furnace according to the invention has an intensive stirring effect in the liquid iron during operation because of the magnetic field and because of its relatively great capacity equalizes the temperature and the analysis of the liquid iron. The present inventive device permits analytical equalization, temperature equalization, analytical correction and quantitative equalization of the liquid iron in one and the same furnace without any additional means; the inventive furnaces are thus also particularly suitable as a duplex-furnace.

While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

1. Induction furnace comprising a furnace body having an internal compartment closed at all sides by said furnace body, said furnace body including a pouring spout communicating with said internal compartment, said furnace body being provided with a central top opening for the continuous receipt of liquid iron, means mounting said furnace body to be tiltable about a single horizontal axis, said horizontal axis of tilt being centrally disposed above the highest level of the liquid iron and passing through the surface of the horizontal projection of the interior of the cross section of the furnace, said opening being arranged at a location through which passes said axis of tilt, in order to maintain a substantially stationary position of the center of said opening during tilting of the furnace to permit continuous receipt of iron, said furnace body being provided with a charging and slagging opening arranged at said body opposite to said pouring spout.

2. Induction furnace comprising a furnace body having an internal compartment closed at all sides by said furnace body, said furnace body including a pouring spout communicating with said internal compartment, said furnace body being provided with a central top opening for the continuous receipt of liquid iron, means mounting said furnace body to be tiltable about a single horizontal axis, said horizontal axis of tilt being centrally disposed above the highest level of the liquid iron and passing through the surface of the horizontal projection of the interior of the cross section of the furnace, said opening being arranged at a location through which passes said axis of tilt, in order to maintain a substantially stationary position of the centerof said opening during tilting of the furnace to permit continuous receipt of iron, said furnace body being provided with a charging and slagging opening arranged at said body opposite to said pouring spout, and door meanssecured to said furnace body for closing said charging and slagging opening.

3. Iron furnace comprising a furnace body having an internal compartment closed at all sides .by said furnace body, said furnace body including a pouring spout ,communicating with said internal compartment, said furnace body being provided with an opening for the continuous receipt of liquid iron, means mounting said furnace body to be tiltable about a single horizontal axis,-saidhorizontal axis of tilt being disposed above the highestlevel of the liquid iron and passes through the surface of the horizo-ntal projection of the interior of :the cross-section of the furnace, said opening being arranged at a location through-which passes said axis oftilt, in order to maintain a substantially stationary position of the centerof'said opening during tilting of the furnace, said pouring spout having a discharge opening, a pivotable-support arranged at the side .of said pouring spout for receiving'a ladle, the pivot axis of said support lying in the vicinity of the discharge opening of said pouring spout, and parallel guide means operatively connected to said support for maintaining the latter in substantially horizontal position during tilting of the furnace for casting.

4. An induction furnace for use with a cupola furnace for supplying molten metal over -a pouring trough comprising a furnace body including a top cover with an opening therein, supporting axis means for pivotally supporting said furnace body for tilting movement about a substantially horizontal axis which is arranged in the vicinity of the central portion of the opening in the top cover, said furnace body having a pouring spout on one side, the opening in said top cover being such that it may be aligned below the pouring trough for supplying liquid metal to the interior of the furnace continuously during all tilting movement of said furnace body.

5. An induction furnace for use with a cupola furnace for supplying molten metal over a pouring trough comprising a furnace body including a top cover with an opening therein, supporting axis means for pivotally supporting said furnace body for tilting movement about a substantially horizontal axis which is arranged in the vicinity of the central portion of the opening in the top cover, said furnace body having a pouring spout on one side, the opening in said top cover being such that it may be aligned below the pouring trough for supplying liquid metal to the interior of the furnace continuously during all tilting movement of said furnace, said pouring spout defining an opening for pouring metal for casting and including a supporting member for a casting ladle, and means connected between said supporting member and said furnace for supporting said support member in an upright position below said pouring spout during all degrees of tilting movement of the furnace.

6. An induction furnace for use with a cupola furnace for supplying molten metal over a pouring trough comprising a furnace body including a top cover with an opening therein, supporting axis means for pivotally supporting said furnace body for tilting movement about a substantially horizontal axis which is arranged in the vicinity of the central portion of the opening in the top cover, said furnace body having a pouring spout on one side, the opening in said top cover being such that it may be aligned below the pouring trough for supplying liquid metal to the interior of the furnace continuously during all tilting movement of said furnace body, and means connected to said furnace for tilting said furnace both forwardly and backwardly, said furnace having a charging and slagging opening on the side thereof opposite from said pouring spout.

7. An induction furnace comprising a furnace body incorporating a cover with an opening adjacent the upper portion of one side defining a pouring opening for casting and with an opening adjacent the upper portion of the other side defining a charging and slagging opening, said cover having a top opening therein for continuously receiving molten iron, means pivotally supporting said furnace body for pivotal movement forwardly and backwardly about a horizontal axis located substantially in the vicinity of the opening in said cover whereby the opening is not displaced materially during the tilting movement of said furnace body so that it may be aligned with means for supplying liquid iron downwardly therethrough, and means connected to said furnace for selectively tilting said furnace forwardly for casting and rearwardly for slagging.

8. Induction furnace comprising a furnace body having an internal compartment closed at all sides by said furnace body, said furnace body including a pouring spout communicating with said internal compartment, said furnace body being provided with an opening for the continuous receipt of liquid iron, means mounting said furnace body to be tiltable about a single horizontal axis, said horizontal axis of tilt being disposed above the highest level of the liquid iron and passes through the surface of the horizontal projection of the interior of the cross-section of the furnace, said opening being arranged at a location through which passes said axis of tilt, in order to maintain a substantially stationary position of the center of said opening during tilting of the furnace, said pouring spout having a discharge opening, a pivotable support arranged at the side of said pouring spout for receiving a ladle, the pivot axis of said support lying in the vicinity of the discharge opening of said pouring spout.

9. Induction furnace comprising a furnace body having an internal compartment closed at all sides by said furnace body, said furnace body including a pouring spout communicating with said internal compartment, said furnace body being provided with an opening for the continuous receipt of liquid iron, means mounting said furnace body to be tiltable about a single horizontal axis, said horizontal axis of tilt being disposed above the highest level of the liquid iron and passes through the surface of the horizontal projection of the interior of the cross-section of the furnace, said opening being arranged at a location through which passes said axis of tilt, in order to maintain a substantially stationary position of the center of said opening during tilting of the furnace, and heating coil means arranged in the lower region of the furnace body.

References Cited UNITED STATES PATENTS 2,674,640 4/1954 Tama 266-38 2,792,602 5/1957 Rossi 164-155 3,183,294 5/1965 Kasper 1327 FOREIGN PATENTS 221,268 7/ 1909 Germany. 729,961 5/1955 Great Britain.

1. SPENCER OVERHOLSER, Primary Examiner.

E. MAR, Assistant Examiner. 

4. AN INDUCTION FURNACE FOR USE WITH A CUPOLA FURNACE FOR SUPPLYING MOLTEN METAL OVER A POURING TROUGH COMPRISING A FURNACE BODY INCLUDING A TOP COVER WITH AN OPENING THEREIN, SUPPORTING AXIS MEANS FOR PIVOTALLY SUPPORTING SAID FURNACE BODY FOR TILTING MOVEMENT ABOUT A SUBSTANTIALLY HORIZONTAL AXIS WHICH IS ARRANGED IN THE VICINITY OF THE CENTRAL PORTION OF THE OPENING IN THE TOP COVER, SAID FURNACE BODY HAVING A POURING SPOUT ON ONE SIDE, THE OPENING IN SAID TOP COVER BEING SUCH THAT IT MAY BE ALIGNED BELOW THE POURING TROUGH FOR SUPPLYING LIQUID 